Enzymatic Hydrolysis of cellulose for production of fuel ethanol by SSF

Presented by Alaaedine Talab

What is SSF?

The reaction

The reaction continuedβ(1→ 4)

Purpose of SSF

• Minimize Hydrolysis byproducts• Economically favorable• Minimize inhibitory factors• Eliminate transfer time

SSF Kinetics

Cellulose cellobiose glucoser1 r2

Experimental Procedure• Effects of specific components of SSF system

• Assays done in Y/P medium (10g/L yeast extract, 20g/L peptone), PH = 5.0 at 38C

• Trichoderma Reesei• Initial rates determined after enzyme

deactivation(20 minutes boiling water, denatur) 15s intervals 1 minute duration

How do we measure enzyme activity as an uncoupled system?

3g/L

We can simplify the volumetric rate constants

=

constant

Effect of cellobiose on cellulase activity

Avg.

Effect of cellobiose on B-glucosidase

K2B?

Effect of cellobiose on B-glucosidase

Maximal rate

Glucose concentration and enzyme activity

Ethanol concentration and Enzyme activity

K2E = NEGLIGIBLE

Summary

Putting it all together

Putting it all together continued

• Almost perfect fit but not yet

• Why?

First order rate loss added to model

• Fail

(Conclusion)So what?

• R^2> 0.98• Developed a quantitative mathematical model

that can predict SSF progress• This applied to enzymes from T. risea however

model can be used to calculate other microbe kinetics

• Can be used for process, design, optimization and scale-up (industrial purpose) to enhance ethanol productivity

Critique

• Take into account Cellulase inactivity• Understand mechanisms of inhibition (i.e.

feedback inhibition)• Use larger concentrations of substrate (max =

120g/L)

References

• http://www.ncbi.nlm.nih.gov/pubmed/18609632

• http://bio-process.com/wp-content/uploads/2009/12/Cellulosic-SSF.pdf